Adaptation of the elaboration of red wines in function of the grape's polyphenolic potential

experiences carried out in the 2001 vintage

Abstract

Tannat, Cabernet-Sauvignon and Merlot red wines were elaborated, at a reduced scale, in the vintage 2001 using grapes from three vineyards of each variety. Extractable anthocyanins contents, total potential in anthocyanins and phenolic richness of the grapes were estimated, according to Glories and Augustin (1993). After that, skins were extracted separately, with a solution of ethanol 12 % pH 3.2, analysing periodically the anthocyanins and total polyphenols concentrations. Two vinifications by vineyard were carried out using 50 kg of grape in each one. Total phenolic and anthocyanic contents of the musts were determined every 24 hours, from crushing to devatting. The duration of the maceration was decided in function of the indexes determined in the grapes and the polyphenols extraction in the laboratory and the winery. Two months after the fermentation had finished, wines determined their colour and phenolic composition. Tannat wines and grapes had significantly the highest contents of polyphenols. Phenolic contents presented a high correspondence among the whole grapes, skins, musts and wines. The correspondence of the characteristics of the wines with the determined indexes in grapes, skins and musts confirms that the estimation of the phenolic potential of the grapes is essential to manage more adequately the fermentation on skins.